On seeing the viral chart, infection control scientist Dr Holly Seal responded: "Tad simplistic? If we move to community mask use … where are the products coming from? Are members of the public going to wear the same masks over and over again?"

Masks are of most use to medical professionals, like Martina Papponetti, 25, a nurse at the Humanitas Gavazzeni Hospital in Bergamo, Italy. Picture: AP Photo/Antonio Calanni

MASKING REALITY

When it comes to this coronavirus, there is no "silver bullet".

Wearing masks may seem a no-brainer but they are only truly effective when used - with brains.

The advice of epidemiologists and doctors may seem counterintuitive but it's based on cold, hard maths.

My babies are too young to read this now. And they’d barely recognize me in my gear. But if they lose me to COVID I want them to know Mommy tried really hard to do her job. #GetMePPE#NYCpic.twitter.com/OMew5G7mjK

"If you wear a mask and cough then your droplets won't go very far. If asymptomatic cause spread, masks may decrease them touching their own nose etc and then surfaces with hand."

Which is why masks need to be available to give to those known to be infected and even here, they must be used correctly.

"If you watch community mask use, you quickly notice that there are great variations in use … and plenty of people touching the mask, not washing hands and then touching the environment," Dr Seale adds. "This practice won't help others."

It's not that widespread mask use is totally worthless. It's just not the highest-value use of this critical resource at this time. If sufficient supplies of N95 masks are eventually secured, widespread distribution will help put the final nail in COVID-19's coffin.

"After many reports of asymptomatic transmission, I think community mask use might have some value. It may prevent spreading infections from asymptomatic cases," says Dr Chughtai.

Masks are only a small part of the equation because COVID-19 is also found on surfaces - particularly of metal or plastic. It's in faeces, so it can get under your fingernails once you've been to the toilet. So … wash your hands. Hard.

FACING THE TRUTH

Masks really aren't all that easy. They're not body armour that stops COVID-19 bullets. And, in the hands of amateurs, they can actually be dangerous.

Boston University epidemiologist Assistant Professor Ellie Murray took to Twitter to detail what goes on.

"Why might masks for all not work?" she asks. "Because masks are actually not that easy to use.

"Virus droplets aren't like dust. You don't have to just stop yourself inhaling them from the air. The virus lands *on* your mask, and if you touch the mask with your hand or face, you can be infected."

Nobel laureate and infectious diseases expert Professor Peter Doherty says the value of widespread mask use has long been disputed.

"Depending on how good a mask it is, it can get kind of wet, you know, dribbles, snot, mucus … all those things that are so important, but we don't regard as being of great value. And if your mask is wet, for instance, and if it did get contaminated, well then maybe you want to drop it down around your neck or something when you're out in really clear and open air … You're at more risk from the mask.

"So I think they're very important for healthcare workers who are up close. I'm not so sure they're that important for the rest of us."

Wondering about the risk of food deliveries during the #COVID19 crisis?

Nobel Laureate @ProfPCDoherty tackles those and many other questions in our latest webcast.

Take the mask off by pulling the strap at the back of your head forward. Don't touch the mask itself. Wash your hands energetically - both before and after doing this.

Remember: the targeted application of masks is just one sandbag in the wall being built against the COVID-19 tidal wave.

"What else is coming?" Dr Murray asks rhetorically. "You or someone you love is probably going to get sick, maybe hospitalised and maybe die. We need to face that possibility and prepare. Be ready to stay home 14+ days while sick, learn when it's time go to the hospital. Learn to cope with grief and loss."